The present invention relates to an image sensing system and control method thereof and, more particularly, to an image sensing system where a camera apparatus and a client device are connected, and a method of controlling the camera apparatus by the client device.
The assignee of the present invention has already developed an image sensing system, where a camera apparatus and a computer are connected via an RS serial cable or the like, for controlling an image sensing direction or zoom ratio of a camera apparatus by panning (rotate on a vertical axis) or tilting (rotate on a horizontal axis) the camera apparatus in accordance with a control command sent by a computer terminal. In such system, the computer includes software for operating a camera apparatus so that it is possible for an operator to operate the camera apparatus from the computer terminal by sending a control command by using a keyboard or mouse or the like.
In a case where the camera apparatus, connected to a computer terminal, includes functions for automatic focus (AF) and automatic exposure (AE), a control command related to AF or AE may be performed from the computer side.
In a case of utilizing a so-called electronic overhead projector (OHP) apparatus which senses an object (document or the like) placed on a platen, the focal point of the camera apparatus is adjusted so that the document placed on the platen is focused.
In the conventional image sensing system, however, the focal point and exposure are normally adjusted to focus the center of a sensing object. Therefore, in order to focus or adjust the exposure for an object which is not in the center of the sensing image, the camera apparatus must be panned or tilted to place the object of interest in the center of the sensing image. Such operation is cumbersome since the position of detection area of the camera apparatus must be adjusted.
Furthermore, in a case where a three-dimensional object is placed on the platen and sensed by the electronic OHP, the focal point must be manually adjusted to focus the portion subjected to image sensing.
Furthermore, there is an image sensing system which improves the quality of the sensed image by obtaining focus data and lightness data. In the image sensing system of this type, conventionally, an image is sensed by detecting a portion of signals of the image to control focusing.
However, in the conventional image sensing system, optical parameters set only for a portion of the image are applied to the entire image. Therefore, in a case where the image includes portions whose depth and lightness greatly vary, the sensed image of these portions are out of focus or exposure is not appropriate. Moreover, in a case where a wide angle image is sensed, a lens having a large field of view angle is generally used. In this case, a similar problem also occurs because the optical parameters are set based only on a part of the image.